Thirty years on, U2 still find relevance in 'The Joshua Tree'

The band, led by 57-year-old singer Bono, is playing the entire record to 2.4 million fans on their 2017 tour, including hits "With or Without You" and "I Still Haven't Found What I'm looking For".

But they started the London show with early songs "Sunday Bloody Sunday", "New Year's Day", "Bad", and the Martin Luther King Jr-inspired "Pride (In the Name of Love)", which Bono dedicated to the "Rainbow people of London" who took part in the annual Pride LGBT march in the city earlier on Saturday.

"The Joshua Tree" was played in sequence against a backdrop of video of U.S. landscapes such as Death Valley, and Americans standing in front of the Stars and the Stripes, shot by Dutch photographer Anton Corbijn who created the imagery on the original record.

The group's best-selling album was released in 1987 when Ronald Reagan was U.S. President and his ideological soul mate Margaret Thatcher was in power in Britain.

The tracks "Bullet the Blue Sky" and "Mothers of the Disappeared" were inspired by trips Bono made to Nicaragua and El Salvador, where he saw the impact of U.S. foreign policy, while "Red Hill Mining Town" was about the impact of the socially divisive miners' strike in Britain in the 1980s.

Lead guitarist The Edge said in an interview with Rolling Stone in January that politically "things have kind of come full circle".

"It just felt like, 'Wow, these songs have a new meaning and a new resonance today that they didn't have three years ago, four years ago'," he told the magazine.

Bono largely let the music speak for itself on Saturday, although a character called "Trump" was called a liar by the "good guy cowboy" in a Western movie-style clip.

"The Joshua Tree", which sold more than 25 million copies, marked the pinnacle of the band tackling social and political issues through rock music.

Their next album, "Rattle and Hum", did not match its success critically or commercially, and the band reinvented themselves in the 1990s by incorporating electronic and alternative rock into their sound.

Seven of their later songs, including "Ultraviolet" and "One", were played as an encore, before Bono invited support act Noel Gallagher back on stage to sing "Don't Look Back in Anger", a song he wrote for his band Oasis.

The track became an anthem for Manchester after 22 people were killed by a suicide bomber in the city in May, and Gallagher also dedicated it to the victims of further attacks and a devastating tower block fire in London in June.

U2, Gallagher and thousands of fans united in singing the anthem, ending a show that proved the enduring relevance and appeal of 1980s and 1990s rock music.